'输给' is a verb phrase meaning 'to lose to (someone)' — it expresses the result of a competition, contest, or comparison where the subject is defeated by another person or group. The first character 输 (shū) means 'to lose', while 给 (gěi) here functions as a directional complement indicating the recipient of the loss — i.e., the one who won. Unlike simple verbs like 'lose', '输给' always requires an explicit object (the winner), making it transitive and inseparable in structure.

This phrase is commonly used in sports, games, debates, exams, or even informal comparisons ('He lost to his younger brother in chess'). It carries a neutral-to-slightly regretful tone and is standard in both spoken and written Mandarin. Note that it does not imply physical giving — 给 here is grammatical, not lexical — so '输给' should never be interpreted as 'give to'.